Real Science Technology. Earth. Level 2, Unit B c.2.
Chicago-čujuhus (17. p.)Real Science Technology. Earth. Level 2, Unit B C.2.
MLA-čujuhus (9. p.)Real Science Technology. Earth. Level 2, Unit B C.2.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.